1. Field of the Invention
The present invention generally relates to a disk array device, and in particular to a disk array device that supplies a direct voltage to the respective hard disk drives via a common power supply bus, and converts this direct voltage into a 12V or 5V direct voltage required for its own operation with a DC-DC converter provided to each of the hard disk drives.
2. Description of the Related Art
Conventionally, a hard disk drive requires two types of direct voltages as the drive voltage; namely, a 12V for driving the hard disk or magnetic head, and a 5V for driving the built-in boards. Thus, with a conventional disk array device that operates a plurality of hard disk drives in a RAID (Redundant Array of Inexpensive Disks) format, 5V and 12V direct voltages are generated in the AC-DC switching power supply positioned at the power supply input of the device, and these are respectively supplied to each of the hard disk drives via a common power supply path.
Nevertheless, with this kind of feeding system, when the 5V or 12V feed line on the common power supply path short circuits in the ground, there is a problem in that the operation of every hard disk drive receiving such feed would stop and cause a system failure.
As a method for overcoming these problems, a method has been proposed for supplying the direct voltage to the respective hard disk drives via two feed lines without separating the feed line for 5V and 12V (providing redundant feed lines), providing a DC-DC converter to each of the hard disk drives, and generating a 5V or 12V direct voltage required for the operation of the disk drive in each of the hard disk drives based on the direct voltage obtained via the feed line (Japanese Patent Laid-Open Publication No. 2004-126972). According to this method, even when a failure occurs to one of the feed lines being used normally, power can be supplied to the respective hard disk drives via the other feed line, and a system failure can be prevented thereby.